New Jersey’s virus transmission rate jumped to the highest in 10 weeks, Governor Phil Murphy said, calling it “an early warning sign” that the state must redouble its efforts to keep Covid-19 from returning.

The state’s measure of transmission, called Rt, stands at 1.03; a rate above 1 means the virus is spreading. With the state gradually reopening in the past few weeks, the rate had been slowly rising since it touched 0.62 on June 11. As the virus took hold in New Jersey in March, each virus-carrying person was passing it to at least five people.

“We need to be smarter, we need to work harder,” Murphy said. “This thing is brutal.” He reminded residents that “face coverings are how we slow the spread of Covid-19,” and said the state was considering an order that would require people to wear masks while outdoors.

New Jersey reported 13,373 dead who had tested positive for the virus. The state added two more fatalities with a probable, though untested, virus link, for a total 1,856.

Though the transmission rate was up, Murphy said, the state had downward trends in three important areas. Hospitalizations over the past 24 hours were 861; at the virus’ peak, more than 8,000 patients were in New Jersey hospitals. Of 187 patients in intensive-care units, 152 were on ventilators.

In Hoboken, across the Hudson River from Manhattan, 12 of 13 new cases were tied to out-of-state travel.

State Health Commissioner Judith Persichilli said “several cases” in Sussex and Warren counties, in northern New Jersey, were traced to a June wedding in Myrtle Beach, South Carolina. Murphy said the New Jersey outbreak demonstrated the need for travelers to self-quarantine after arriving from 16 states where cases have spiked.

“Follow the recommended 14-day quarantine period,” Murphy said. The self-isolation, he said, can prevent “the start of an outbreak in your local communities.”

This article was provided by Bloomberg News.